Electric heater.



C. S. STEWARD,

ELECTRIC HEATER.

APPLICATION FILED Amm. 1914.

1,104,572. Patented Ju1y 21, 1914.

CLARENCE STE'WARD, 0F CHANTEA-NGCJGRA,l '11ENNEBSEIE.`

ELECTRIC HEATER.

Specification of Letters Patent.

Patentnddniy 21, 1914.

Application led'ApIil 8, 1914i Serial H0. Swl

To all 'whom it may con cem Be it known that I, CLARENCE S. S'rnwann, a citizen of the United States, residing at Chattanooga, in the countyoffHamilton and yState of Tennessee, have invented. certain wwe anch useful Improvements in Electric .being had to the 'accompanying drawings,

and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to new and useful improvements in electric heaters and the object in view is to produce a device of this na ture, comprising a plate of steatite or other material which is provided with a series of concentric slots formed in the upper surface thereof and chambered for the reception of independent heating coils, so arranged that separate currents may be passed through either or all of the coils atthe same time according to the degree of heat desired.

More specifically, the present invention comprises an electric heater inv which separate heating coils are provided, one contained within another in concentric slots, widened to form chambered portions for the reception of the wiring, and connection between the partitions intermediate the chambered portions being formed by boring holes from the periphery of the plate through the various chambers.

`My invention is illustrated in the accompanying drawings, in which:

. Figure 1 is a top plan view.- Fig, 2 is an edge View, and Fig. 3 yis a sectional view` on line 3-8'0f Fig. 1.

l Reference now being had to the details of the drawings by letter, designates a plate of steatite or other suitable material which is provided with a series of concentrically formed grooves B, B, the lower portions of which are widened to form chambers, and

which are adapted to receive a heating coil D, which coil passes through registering ducts E, E formed in the partitions intermediate the concentric slots B. One end of vthe wire is connected to av terminal F and its other end is connected to s. terminal G.

Other concentrically formed slots, desighated by letter H, are surrounded lby the and each slot H is ch'ambered for the reception of the heating coil K, which passes through registering slots L formedinthe partitions intermediate the slots H. One end of the coil K is' fastenedto a terminal- S and its-other end is fastened to a termi nal S. l

Eythe provision of anv electric heater made in accordance with my invention, it will be noted that coils are provided through which separate circuits may be passed accordingly as it may be desired to heat one coil of wiring or the other, the central coil K being provided for the purpose of heating receptacles of smaller diameter than the outer coil, or all coils together may be utilized when it is desired to obtain a greater degree ci heat than could be obtained by the use of a single coil.

lVhile in the drawings I have shown a. unit constructed of two separate circuits, it will be understood that I do not conne myself to any number of circuits, as obviously any number may be used and ar-v ranged in any suitable manner within the heating,r plate.

By the peculiar arrangement forming the holes or ducts through the partitions in the slots, by simply boring a hole from the edge as shown, the cutting away of the partitions upon the. top is avoided, thus leaving a. smooth upper surface, the wiring being passedthrough holes and connected to the terminals in the manne-r shown. By this .arrangement oi' heater, the bottom is irnis provided to allow the various parte to cie pand and contract without likelihood of the surface of the plate checking or cracking.

`|iVhat I claim to be new is: l. An electric heater comprising a single piece of steatite or other suitable material having a series of concentrically formed slots in the upper surface thereof and which slots are widened toform chambers, said chambers communicating with each other through ducts formed in the walls thereof, terminals passing through apertures in the bottoms of the ducts, the other portions of the bottoms being imperforate, coiled wires mounted in said chambers and passing through said ducts in the walls, said coils receive separate circuits to regulate the degree of heat. A

2. An electric heater comprising a single piece of steatite or other suitable material 5 having a series of concentrically formed i0 terminalsv passin through apertures in the bottoms of the ucts, the other portions of the bottoms being mperforate, coiled wires kmounted in said chambers and passing terseeting grooves formed at right angles to i each other in the tops of the Walls intermediate the slots.

In testimony whereof I hereunto aix my Signature in presence of two witnesses.

CLARENCE S. STEWARD. Witnesses:

J, H. VVooDY, IDA MCCARRON. 

